Textiles reacted with methylol perfluoroalkanamides



United States Patent a corporation of Delaware No Drawing. Filed Aug. 12, 1963, Ser. No. 301,597

7 Claims. (Cl. 8-1163) The present invention relates to the preparation of monoand di-methylol perfiuoroalkanamides and to textiles to which the aforesaid methylol compounds are aflixed.

For centuries man has sought to alleviate the discomfort concomitant with exposure to rain. One hundred years ago Maclntosh provided the coated fabric which has, in subsequent years, provided a generic name for a particular class of rainwear. -It was not until about 1935 that there was any attempt to discover the factors controlling resistance to wetting by water. Prior to this time, textile materials were coated fabrics with various cookbook recipes such as rubber, linseed oil-rubber mixtures, empirical and whimsical synthetic dopes and other compositions having no basis in a discovery of the physical properties of a preparation which would impart to a textile the capability of water repellency. Without understanding the basic principles of surface free energy, contact angle, and spreading coeflicient several unrelated practical developments arose during the half-decade from 1935 to 1940 which changed the art of Water-proofing textiles. In Germany, a series of parafiin wax emulsions were developed which, when padded onto textiles, produced a high contact angle of Water drops on the surface and a high degree of shower resistance Without changing the porosity or air permeability of the textile material as do the preparations recommended for waterproofing prior to 1935. The treated fabrics were nonwettable by water and water-borne liquids and stains because of the change of the free energy of the fiber surfaces and not because the interstices of the woven fabrics were plugged. Thus, a practical improvement was made without an understanding of the reason for the advance in the art.

By the use of these new wax emulsion-metallic salts mixtures, it was then and is now possible to produce fabrics which have the feel and appearance of conventional fabrics but do not look like oil-cloths or fabrics having rubberized coating. The only practical limitation of such mixtures is the durability to washing and drycleaning. This class of water-proofing materials generally comprises a mixture containing:

(a) A paralfin wax or mixtures of vegetable wax esters such as carnauba, candelilla, or sugar cane wax.

(b) An emulsifying agent, usually glue, gelatin, and rosin soaps.

(c) An aluminum or zirconium salt, usually the formate or acetate. The primary function of the salt is to insolubilize the glue and other emulsifiers after the emulsion is deposited on the fabric.

A large variety of such products are still in use as low-cost, non-durable water repellents for textiles. Since neither thermosetting nor fiber reaction occurs when textiles are coated with such products, the treated textile is non-durable to washing and dry cleaning. Other than water repellency for rainwear fabrics, such mixtures provide fabrics with a fair degree of spot and stain resistance to water-borne chromophoric materials.

3,322,490- Patented May 30, 1967 The search for durable or permanent water repellents as contrasted with these non-durable water repellents, especially for cellulosic fibers was initiated by the need to overcome the deficiencies of these wax emulsionrnetallic salt mixtures. The first major advance occurred in England where a product marketed under the tradename Velan was produced. This material was octadecyloxymethyl pyridinium chloride, a quaternary ammonium compound made by the chlorornethylation of octadecanol, followed by quaternization with pyridine to yield a product having a composition represented by the formula This compound, unlike other quaternaries, is unstable and under acid conditions reacts with surfaces containing active hydrogen, e.g., the hydrogen of a hydroxyl group in cellulose fibers. If the cellulose molecules be represented by Z(OH) then the reaction can be considered to be summarized by the equation:

where py is the balance of the pyridine ring. Fabrics treated with such a compound are durably water repellent, are porous, soft, and have the appearance of untreated fabrics.

A major improvement of the Velan type material was made when the stearamidomethyl analog of Velan (In-H350 ONHOHQN/ commercially known as Zelan and Norane R was produced. The advantage of the stearamide product is greater initial water repellency and greater durability to washing. Such products are still among the forefront of the leaders in rainwear fabric finishes.

In the search for other fabric-reactive or durable water repellents other classes of compounds have been developed. Illustrative of these other classes of water repellents are the silicon water repellents methylolstearamide compositions (Permel, Ahcovel NW), hydrophobic resins (Norane GG, Ranedare R, Argus DWR), octadecylketene dimer [Aquapel] and others.

While durable water repellents had been initially developed for outerwear and raincoat applications, it was soon recognized that durable water repellents could be used as finishes for other purposes. In the period 1950 to 1956 these durable water repellent finishes were widely used on mens suitings, dress goods, and upholstery materials. When offering these products to the textile finishing trade, promotional emphasis was not placed on water-repellency but on spot-and-stain resistance. This use has continued to the present time. It had been observed that fabrics treated with such durable water repellents had a high degree of resistance to soiling by water-borne soils and stains and were easier to launder. The primary limitation of these finishes was that they attracted rather than repelled oily soils, and the treated fabrics were not resistant to staining by oily materials such as oils, greases, gravy, mayonnaise, etc.

'In the early part of the 1950 decade based on work done at Naval Research Laboratory by Fox and Zisman and from work done at a division of the Minnesota Mining and Manufacturing Co., the utility of certain fluoro- 3 carbon based chemicals as fibrous finishes was announced. Fox and Zisman had demonstrated the physiochemical principle of low free energy surfaces and the relation of non-wetting with water or oils of surfaces treated with chemicals containing perfluoroalkyl groups.

The practical developments of 3M culminated in the introduction of the first product for textile treating. This product is still known as FC-149 and is a classical Werner complex of a carboxylic acid made by reacting one mol of the acid with two mols of basic chromic chloride. The compound is water soluble and cationic in nature. It exhibits strong adhesion to anionic substrates such as cellulose and fiberglass. It also complexes with pro teinaceous fibers such as Wool, silk, and leather to give both water and oil repellent surfaces. It is generally believed that perfiuorodecanoic acid is the base for this product.

Subsequently, 3M made a product known as PC- 208 available as a finish. It is generally believed that this finishing material is a perfluorosulfonamide having a composition corresponding to the formula where x is an integer in the range of 3 to 13, R is methyl, ethyl, propyl, butyl, amyl, hexyl, R" is an alkylene radical having 1 to 12 carbon atoms and R is hydrogen, methyl, or ethyl.

The advent of these perfluoro finishes produced a great practical improvement in fabric finishes. Although of little merit for plain water repellency for outerwear purposes, the two products, i.e., the Werner complex and the perfluorosulfonarnide, offer a solution to the problem of providing fabrics with water-and-oil repellency and practical resistance to staining. Because of its hydrolytic instability the Werner complex has been limited to wool, leather, and upholstery finishes. The sulfonamide has become a leader in finishes for cotton, rayon, and non-cellulosic synthetic fiber.

Important as water-and-oil repellency and resistance to staining by water-and-oil borne stains are for wearing apparel, upholstery and the like, the capability of shedding oily particulate soil is of greater importance. That is to say, the finely divided environmental grime mixed with the oil exudations of the human skin, i.e., oily particulate soil, soil the neckband and cuffs of a mans shirt are far more often encountered than soiling with gravy or mayonnaise. Hence, while fabric finishes which repel water, oil, waterborne and oil-borne stains are of great importance, the capability of resisting staining by oily particulate soil is of greater importance for aesthetic reasons if for no other reason. Yet even the perfluoro finishes presently available do not have the capability of resisting staining by oily particulate soil. In fact, they enhance such soiling.

It is manifest that controlled evaluating of fabric finishes in actual use is not possible. Consequently, it has been necessary to use evaluation methods subject to laboratory control which will simulate as closely as possible actual conditions under which water-repellency, oil-repellency, resistance to staining by water-borne and oil borne stains, and resistance to staining by oily particulate soil of treated fabrics occurs. Such methods of evaluation are the following.

WATER REPELLENCY Resistance to Wetting (Spray Test) AATCC Standard Test Method 22-1952 This test is applicable to any textile fabric. It measures the resistance of fabrics to wetting by a water spray and the results depend primarily on the degree of hydrophobicity inherent in the fibers and yarns and subsequent treatments to which the fabric is subjected. Water is sprayed against the taut surface of a test specimen. Evaluation of the wetted pattern is readily brought about by comparing the wetted pattern with standard wetting pattern pictures:

Rating: Characterized by upper and the lower surfaces.

The test specimens of minimum size of 7" x 7" (seven inches by seven inches) are conditioned at 70 F. and 65 percent relative humidity for a minimum of four hours before testing.

The test specimen, fastened securely and wrinkle-free in a metal hoop having a diameter of 6 inches, is placed and centered 6 inches under a standard spray nozzle at an angle of 45 to the horizontal. Two hundred and fifty milliliters of water at :2" F. is poured into a funnel attached above the spray nozzle. The spray lasts 25 to 30 seconds at the end of which time the hoop is taken by one edge and the opposite edge tapped smartly once against a solid object with the wet side facing the solid; this procedure is repeated with the hoop reversed 180.

OIL REPELLENCY 3M Textile Chemicals Appendix ATest Methods, page 1 Oil Repellency Percent IIep- Percent Nujol" Rating tane (by (by volume) volume) 1 N0 hold out to Nujol."

The standard oil-heptane mixtures are contained in small stoppered medicine-dropper bottles. A drop of each mixture of Nujol and heptane is placed on the fabric. The appearance of the test oil is observed through the drop. Note is made whether wetting or penetration occurs. The number corresponding to that mixture containing the highest percentage of heptane which does not penetrate or wet the fabric after three minutes is considered the oil repellency rating of the system.

The change in the optical refractivity of the drop is often an indication of wetting. In some cases wetting can be better determined by observing the other side of the fabric. In some cases reported hereinafter the term 0+ has been used to indicate a modicum of resistance to wetting by oil.

STAIN REPELLENCY The following procedures have been used to establish the degree of resistance to staining by water-borne and oil-borne stains of fabrics.

(a) The fabrics were stretched lightly on 12" x 31" frames. All or part of the frame was used depending upon the amount of fabric available. The frames were supported at both ends with the fabric about 8 inches above a black surface. The fabric touched nothing.

(b) Three inch medicine droppers were used to draw the stains from the containers. A 1 cubic centimeter calibration was established and marked on the exterior of each dropper. The stains were squeezed vertically downward from a height 2 inches above the cloth.

(c) After five minutes the unabsorbed stain was wiped off the fabric with two sweeps of Kleenex and the stains rated as follows:

Appearance: Rating No stain visible Slight stain 4 Easily noticeable stain 3 -Considerable stain 2 Very heavily stained 1 (The spread or lack of spread is not necessarily reflected in the ratings.)

(d) Duplicate sets of stains were applied in separate areas so that one-half of the fabric could be washed. In most instances, the wash was carried out with 50 grams of Fab, a cotton cycle, and a dummy load to total 5 pounds in a Norge Home Automatic Washer.

(e) The following two lists describe the numbering and the gross characterizations of the stains employed. Water stains:

(1) Instant tea 1 (2) Sheaifers 232 Blue-black Skrip (3) A & P Concord Grape Juice (4) Ann Page Salad Mustard (5) Bosco chocolate syrup Oil stains: (6) Wesson Oil (7) Gulf Supreme Motor Oil 20/ 20 (8) Oleomargarine 2 (9) La Ros Tomato Sauce (10) Jergens Lotion 1 8 cc. dry powder/200 cc. water applied at 160 F.

2 Melted and applied at 160 F.

In reporting the relative resistance to staining and ease of stain removal in laundering, the staining values for water-borne and oil-borne stains were averaged separately.

In all cases the stains were allowed to dry on the fabrics for twenty-four hours before laundering.

OILY PARTICULATE SOIL REPELLENCY (GRC Dry Soil Test) Fifteen to twenty 6" x 8" numbered speciments (normally 80 x 80 cotton), including at least one untreated control, are tumbled for thirty minutes with 10 percent of Cyanamid Soil based on the weight of the fabric. The tumbling is carried out in a 5 liter capacity Five Minute Home Cleaner at 44 rpm; six No. 8 neoprene rubber stoppers are distributed among the speciments to increase the mechanical action. At the end of the tumbling, the specimens are removed and each shaken separately up and down fifteen times by hand to remove surface dirt.

The specimens are then cut in two (to produce two 4" x 6" pieces). One-half is washed with 50 grams of Fab in a cotton cycle with a S-pound dummy load, then hung to dry and lightly ironed under a clean cotton cloth.

The degree of soiling is determined with a Photovolt Reflectance Meter (Tri Blue Filter). Six reading per specimen are made and the arithmetic average reported.

The Cyanamide Soil described below is the same as that recommended by Minnesota Mining and Manufacturing Co. The following dry ingredients are blended thoroughly, dried in a forced draft convection over for eight hours at 50 C., then milled for twenty-five hours with ceramic balls and stored in a polyethylene bag.

Cyanamide Soil Material: Percent by weight Peat moss 38 Cement 17 Kaolin clay 1 17 Silica, 200 mesh 2 17 Furnace black 1.75 Red iron oxide 4 0.50 Mineral oil 8.75

1 Peerless. R. 'l. Vanderbilt.

Davison Chemical Co.

8 Molacco, Benny & Smith Co.

4 C. K. Williams '00.

It has now been discovered that fiber reactive monoand di-methylol perfluoroalkanamides which are formaldehyde derivatives of highly fluorinated (at least 75 percent) amides will produce water, oil, water-borne, oilborne and oily particulate soil repellent surfaces when aflixed to textiles having surfaces containing active hydrogen. Thus, perfluoroalkanamide is reacted with formaldehyde to form methylol compounds or in the proportion of 1 mol of amide to 1 to 2 mols of formaldehyde and 1 to 2 mols of a lower aliphatic alcohol or cycloaliphatic alcohol to form alkoxymethyl derivatives. The reactions can be represented by the following equations:

QCONHz CHzO ROH QCOgRCHfiR H2O or (B) QCONH 2CH O +2ROH QCON CH OR) 2H O where Q is a perfluoroalkyl group having three to twentyone carbon atoms and seven to forty-three hydrogen atoms of which at least 70 percent of said hydrogen atoms has been replaced with fluorine atoms and the terminal group is CHF and preferably CF The perfluoroalkanamide can be prepared from the perfluoroalkanoic acid by reaction with ammonia or by any of the classical methods for producing carboxylic acid amides. For example, isobutylperfluorobutanoate,

CF CF COOCH CH (CH 2 was dissolved in ethyl ether and benzene. The solution was saturated with dry ammonia gas (dried with soda lime). Upon distilling otf the ether a precipitate was formed. The precipitate was washed with toluene to remove unreacted ester andthe isobutanol formed. The washed precipitate was recrystallized from toluene. The perfluorobutanamide had a melting point of 104 C. The literature gives the melting point as 105 C.

Similarly, perfluorooctanamide was produced from butyl perfluorooctanoate, CF (CF COOBu, and dried ammonia gas (dried with soda-lime). Butylperfluorooctanoate was dissolved in ethyl ether and charged to a flask cooled in an ice-salt bath. After no more ammonia gas was absorbed by the solution of the ester, the ether was removed by distillation. (The melting point of the amide is higher than the boiling point of butanol.) After the removal of butanol the still residue was recrystallized from a mixture of toluene and anhydrous Solox in the ratio of 60 to 40 by volume. (Solox is said to be an alcohol base general-purpose solvent consisting of parts especially-denatured alcohol, 5 parts ethyl acetate, and 1 part aviation gasoline. Anhydrous 200 grade is made from 200-proof denatured alcohol and has a specific gravity 0.7997, a distillation range of 75-80 C., and a flash point of 42 F.) The yield was 35 percent of theoretical. The amide had a melting point of 138 C. as given in the literature.

Alternatively, benzene can be added to the reaction mixture after the removal of the ether and the crude amide precipitated, separated from the benzene-reaction mixture, washed with cold benzene and recrystallized from a Solox-benzene mixture (4 to 1 by volume). The yield in this manipulation being 55 percent of theoretical with a melting point of 142 C.

The butyl perfiuorooctanoate can be dissolved in benzene, the solution saturated with dry ammonia, and the amide crystallized from Solox-benzene with a yield of 32 percent of theoretical. A further alternative method involves dissolving the perfluoroalkanoate in toluene, saturating the solution with dry ammonia, and recrystallizing the amide from a mixture of parts by volume of toluene to 1 part by volume of ethanol. The yield of amide in this modification is 49 percent of the theoretical.

From the perfluoroalkanamide the monomethylol derivative of the perfluoroalkanamide can be prepared by reacting the amide and formaldehyde in the molar proportion of 1 to an excess of 1, e.g., 1.5 mols of formaldehyde. Thus, the monomethylol derivative of perfluorobutanamide was prepared.

About 110 grams of isopropanol containing 0.1 mol of perfluorobutanamide were charged to a 500 milliliter three-neck flask equipped with a stirrer, a condenser, and a thermometer. The pH of the alcohol was lowered to 1.0 by the addition of two drops of 50 percent hydrochloric acid. The paraformaldehyde was added and the reaction mixture heated to reflux. After twenty minutes of refluxing the paraformaldehyde dissolved and the mixture was cooled to room temperature. The pH of the reaction mixture was then adjusted to pH 10.9 with dilute caustic soda. The alkaline reaction mixture was refluxed for one hour and a hazy colorless solution obtained. Ninety-four percent of the formaldehyde had reacted as was found by titration.

The dimethylol derivative of perfluorooctanamide was prepared as follows:

The pH of 110 parts by weight of iropropanol was adjusted to pH 1.0 by the addition of two drops of 50 percent hydrochloric acid. The perfluorooctanamide (0.1 mol) was added to the acidic isopropanol and the solution charged to a three-neck flask equipped with a stirrer, a condenser, and a thermometer. Two-tenths of a mol of paraformaldehyde was charged to the flask and the flask heated to reflux for twenty minutes to dissolve the paraformaldehyde. The flask and contents were cooled to room temperature and dilute caustic soda added to adjust the pH to 10.9. The alkaline reaction mixture was heated at reflux temperature for one hour when the solution was clear. When the reaction mixture is cooled to room temperature it forms a jelly. Determination of the free formaldehyde in the reaction mixture showed that 97 percent of the formaldehyde had reacted.

The dimethylol derivative of perfluorobutanamide was prepared in the same manner as the monomethylol derivative except that the mo] ratio of amide to paraformaldehyde was 1 to 2 rather than 1 to 1.5. Determination of the free formaldehyde in the reaction mixture showed that 95 percent of the formaldehyde had reacted.

It is to be observed that the methylol derivatives of the perfluoroalkanamide of the present invention are waxy solids insoluble in water but soluble in lower aliphatic alcohols such as propanol and isopropanol, hydrocarbons such as benzene, toluene, and xylene, and ketones such as acetone. This property of being insoluble in water,

if no other, distinguishes the present methylol derivatives II II 2011 RooH I-ozooILf-o-q ROH where Q has the same significance as in (A) supra, R is H and an alkyl group having one to six carbon atoms, and R is hydrogen or an alkyl group having one to six carbon atoms.

(2) II II Z(OH): ROCHzif-C-Q Z(OCH2)zNC-Q, 2ROH where Q has the same significance as in (A) supra and R and R are hydrogen or alkyl groups having one to six carbon atoms.

The methylol derivatives of the perfluoroalkanamides of the present invention are reacted with the active hydrogen of the substrate, e.g., cotton in the presence of acidic catalysts such as ammonium chloride, oxalic acid, zinc nitrate, lactic acid, and the like at a temperature in the range of about 80 to about 300 F. for a time inversely proportioned to the temperature. For example, employing lactic acid the time is twenty-four hours at room temperature. It will be observed that the catalysts are strong acids or salts of strong acids which hydrolyze to give an acid reaction. Thus, neither ammonium acetate nor sodium chloride is a catalyst for this purpose. Thus, for example, the monomethylol derivative of pentadecafluorooctanamide was affixed to cotton employing various acidic complexes to give the water, oil, and oily particulate soil repellencies indicated in the following table:

Cured at Room Temperature Cured five minute at 300 F.

Concentration of Catalyst and M ethylol Derivative, Concentration, Reflectance Reflectance Percent by Weight Percent by Weight Oil Oil Repcllcncy Repelleney 1 A+ B A+ Control Untreated 0 35 79 0 35 79 1 mono 2 MgClz-6H2O 100+ 100+ 50 82 1 m0no 2 MgClr-GHzO 100+ 48 73 100 42 73 1 m0no.- 0.5 H PO 47 73 0 40 71 1 (30% stearic acid- 100+ 49 70 0 36 58 chrome complex) 1 Di 0.3 NH4O1----. 0+ 42 79 0 40 79 1 Di 0.6 MgClz-fiHzO 0+ 42 79 0 43 78 1 Monomethylol derivative. BBefore washing. A-A

particulate soil adheres.

2 Dimethylol derivative.

fter washing. the higher the numerical value, the less oily From the foregoing description of the present invention those skilled in the art will recognize that novel monoand di-methylol derivatives of perfiuoroalkanamides have been described having compositions corresponding to the formula where Q has the same significance as hereinbefore in Equation A, R is hydrogen, a monovalent alkyl group having one to six carbon atoms or a cycloalkyl group having five or six carbon atoms, and X is hydrogen, a monovalent alkyl group having one to six carbon atoms, and CH OR. Those skilled in the art will also recognize that substrates having active hydrogen in the surface have had repellency to oil, oil-borne stains and oily particulate soil conferred on or imparted thereto through the chemical bonding to the substrate of a perfluoro moiety having a composition corresponding to the formula or corresponding to the formula where Q has the significance as stated hereinbefore in Equation A, and R is hydrogen, an alkyl group having one to six, or a cycloalkyl group having five to six carbon atoms.

What is claimed is:

1. Oil repellent and oily particulate-soil repellent textile comprising a textile polymer having as part of the polymer molecule reactive hydrogens for which there has been chemically substituted a plurality of radicals selected from the group consisting of where Q is a perfluoroalkyl group having three to twentyone carbon atoms and at least two to fifteen fluorine atoms in said alkyl chain and the terminal group in the perfluoroalkyl chain is selected from CHF and -CF and R is a member of the group consisting of hydrogen, alkyl group having one to six carbon atoms and a cycloalkyl group having five to six carbon atoms.

2. Oil repellent and oily particulate-soil repellent textile comprising a textile polymer having as part of the polymer molecule reactive hydrogens in the surface of said polymer, said reactive hydrogens having been chemically substituted by a plurality of radicals selected from the group consisting of Q,CITI-OHZO and QCN-CH2O (I-I) R, (N) 61120-- where Q is a perfiuoroalkyl group having three to twentyone carbon atoms and at least two to fifteen fluorine atoms in said alkyl chain and the terminal group in the perfluoroalkyl chain is selected from CHF and CH and R is a member of the group consisting of hydrogen, alkyl group having one to six carbon atoms and a cycloalkyl group having fixe to six carbon atoms.

3. The oil repellent and oily particulate-soil repellent textile set forth in claim 2 where O is CF (CF 4. The oil repellent and oily particulate-soil repellent textile set forth in claim 2 wherein Q is CF (CF 5. The oil repellent and oily particulate-soil repellent textile set forth in claim 2 wherein at least the major portion of said textile is cellulose.

6. The oil repellent and oily particulate-soil repellent textile set forth in claim 3 wherein at least the major portion of said textile polymer is cellulose.

7. The oil repellent and oily particulate-soil repellent textile set forth in claim 4 wherein at least the major portion of said textile polymer is cellulose. 

1. OIL REPELLENT AND OILY PARTICULATE-SOIL REPELLENT TEXTILE COMPRISING A TEXTILE POLYMER HAVING AS PART OF THE POLYMER MOLECULE REACTIVE HYDROGENS FOR WHICH THERE HAS BEEN CHEMICALLY SUBSTITUTED A PLURALITY OF RADICALS SELECTED FROM THE GROUP CONSISTING OF 